Tortellini In Creamy Courgette Sauce

• 1 onion (finely chopped)
• 1 courgette (sliced)
• 1 clove garlic (minced)
• 130 gr tortellini any filling
• 130 gr creme fraiche
• 75 gr tuinkruiden cheese
• 14 gr butter
• 1 gr marjoram